Distributed generation with its various distributed resource technologies has many advantages when connected with the electric power system (EPS). However, this integration has introduced many issues that should be considered when designing distributed generation. A topic of research is monitoring and security analysis in order to assist Independent System Operators (ISOs) and Regional Transmission Organizations (RTOs) in managing their networks.
The main objectives of monitoring systems are to: a) assist system operators in managing information overload, b) assess dynamic stability and c) provide guidance to operators on how to handle previously unknown situations rapidly. An IEEE task force report discusses past experience of utilities with power system disturbance monitoring and defines requirements of instrumentation for monitoring the data. With the recent advances in real-time systems it is now possible to implement real-time dynamic synchronized data recorders to assess impacts of disturbances over wide. Existing projects provide elegant solutions based on analysis of the data and obviate model parameter construction, as parameters are measured in real-time. However, assessments of existing projects and their responses are determined centrally and, therefore, require sophisticated wide-area measurements and high-speed communication links between the measurement points.
Another of the issues is the islanding of operations and their detection techniques to provide management of the EPS to minimize disruption to customers, and potential damage to the distributed resources.
Islanding is a situation that occurs when part of a network is disconnected from the remainder of EPS but remains energized by a distributed resource (DR). Failure to trip islanded DR can lead to a number of problems for this resource and the connected loads. The current industry practice is to disconnect all DRs immediately after the occurrence of islands. The main concerns associated with such islanded systems include:                the voltage and frequency provided to the customers in the islanded system can vary significantly if the distributed resources do not provide regulation of voltage and frequency,        islanding may create a hazard for the utility workers by causing a line to remain energized,        the distributed resources in the island could be damaged when the island is out-of-phase reclosed to the EPS, and        islanding may interfere with the manual or automatic restoration of normal service for the neighboring customers.        
The criteria of the tripping time for the islanding protection is defined such that the two systems (EPS and DR) should have been successfully separated before any automatic reclosing equipment can attempt to reconnect them when the two networks are out-of-synchronism. The maximum separation time has been specified as 0.5 s. However, the target tripping time of protection algorithms is to be less than 0.125 s as required by some utilities. In general, islanding detection techniques can be categorized into three main groups, namely: passive schemes, active schemes, and communication-based schemes.
First, the passive scheme makes decisions based on the local measurements of voltage and current signals. The algorithms of this scheme include under/over frequency, under/over voltage, rate-of-change of frequency, rate-of-change of power, vector surge and harmonic distortion indices. Next, the active schemes, in these schemes disturbances are injected locally into the system and responses of these disturbances are used to detect islanding conditions. Active schemes include impedance measurement, voltage phase jump, voltage shift, phase shift, frequency shift and harmonic distortion. Finally, the communication schemes are telecommunication devices that are designed to trip DRs when islands are formed. These schemes include power line signaling and transfer trip.